In a conventional switching power supply, an AC input voltage is typically rectified by a rectifier bridge, such as a full bridge or a half bridge. FIG. 1 illustrates a schematic diagram of a rectifier bridge used in a switching power supply. The rectifier bridge, for example, a full bridge, includes four diodes D1, D2, D3 and D4 which are connected with each other as an electrical bridge and packaged as a chip. In a rectification cycle, the diodes D1 and D4 conduct during a positive half sine wave, and the diodes D2 and D3 conduct during a negative half sine wave. Due to forward conduction characteristics of the diodes, an AC input voltage of the switching power supply is converted into a pulsed DC output voltage which is supplied to the subsequent power stage 103.
Although the rectifier bridge has a low cost, it has a large size and causes a power loss which in turn decreases power efficiency.